A control apparatus for controlling an electric power converter is known which comprises: a PWM rectifier which performs a conversion of an alternating current to a direct current; and an inverter connected to the PWM rectifier to perform an inversion of the direct current to the alternating current, the control apparatus including: bi-phase modulation means for generating an output voltage command to perform a bi-phase modulation for the inverter; first compensation quantity calculating means for calculating a compensation quantity correcting the output voltage command in order to compensate for an output voltage error generated when the bi-phase modulation for the inverter is carried out; inverter PWM pattern generating means for generating PWM pulses for semiconductor switching elements of the PWM rectifier on a basis of an input current command; switching detecting means for detecting a presence or absence of a switching of the PWM rectifier; voltage magnitude detecting means for detecting a voltage of a maximum phase, a voltage of a middle phase, and a voltage of a minimum phase from an input voltage of each phase; and polarity determination means for determining a polarity of a load current, wherein the first compensation quantity calculating means calculates the compensation quantity correcting the output voltage command using an output of the voltage magnitude detecting means, an output of the polarity determination means, an output of the switching detecting means, a switching frequency of the inverter, and a dead time.
However, such a problem occurs that the known control apparatus for the electric power conversion device compensates only a voltage error generated according to a commutation but cannot prevent a commutation failure itself.